Method of and apparatus for sealing-in incandescent lamps and similar articles



INCANDESCENT H. REMANE METHOD OF AND APPARATUS FOR SEALING-IN LAMPS ANDSIMILAR ARTICLES Flled Aprll 1925 Invenror: Hermann Re man yHisArrorneg.

' Patented Feb. 5, 1929.

UNITED STATES 7 1 1 1,3 8 PA ENT OFFICE.

HEBMANN BEMAN'E, OF WINTEBTEUR, SWITZERLAND, ASSIGNOR TO GENERAL ELEC-TRIO COMPANY, A CORPORATION OF NEW YORK.

METHOD OF AND AIPABATUS SEALING-IN INCANDESCENT LAMPS AND SIMILARARTICLES.

Application filed April 7, 1925, Serial No. 21,312, and in Germany May7, 1924.

The sealing-in of the stem into the glass bulb of electric incandescentlamps and sim-' ilar glass containers or vessels by the application offlame and continuous rotation of 5 the parts to be sealed together was,according to previous practice, accomplished by sealing the stem to theneck of the bulb, either at the edge of the neck as in the short neckmethod,

or else at a point about half way up the neck as in the long neckmethod. In the latter kind of sealing-in, as shown for example in U. S.

patent to Mitchell and White, 1,453,594, May

- 1, 1923, it is customary to use bulbs with a rather elongated neck.Although the excess length of neck caused a considerable loss of glass,this mode of sealing the parts together was preferred in practicebecause the sealingin could be done with reater safety and reliability,and the burnef gases from the burner flames did not enter the lamp andthus were prevented from injuring the sensitive metallic parts insidethe lamp.

In accordance with this invention, the advantages of the long neckmethod of sealing the parts together inside the neck instead of at theedge is preserved, in spite of the use of a bulb with a short neck. Withthis end in view, according to'the invention and before the sealing-intakes place, the short neck of the bulb is gripped at its lowermost edgeina novel manner by the fingers of a gripping device, and the neck iselongated by subjecting it to the action of a pulling member joined tosaid gripping device, which, after the neck of the bulb has beensufliciently softened by burner flames playing on it, preferablytangentially, moves to elongate the neck, the pulling member beinglimited in its movement. This pulling movement is dis- 40 continued assoon as the neck has been sufficiently lengthened, and the pullingmember then holds the neck by means of the gripping device, withoutexerting further tension on it. The slight constriction of the'neckproduced by capillarity and flame pressure, in

spite of the action of the pulling member, is

not objectionable, and after the pulling stops,

the neck can be safely sealed to the stem, the

excess length of bulb neck being afterwards cut ofi in well-known mannerby mechanical action, air pressure, or narrow and pointed flames. Y

- In order to. facilitate the lengthening of the short bulb neck, and toobtain more safely a .and the filament supports 0.

uniform thickness of the wall, a preferable plan is to elongate the bulbneck by stages by passing it consecutively through a number of workingositions.

. The possi ility' afforded by the means pro-Y vided in this inventionof sealing-in the stem at a point in the interior of the neck. oven inbulbs with a particularly short neck, offers great economies, making notonly for simplification and cheapening of the bulb, but also allowingrealization of great savings in glass and cost of transportation ofbulbs from the I glass works to the lamp factory where they are to beused. Another substantial advantage of the new scaling-in method isthat, on the one hand, crooked sealing-in of the stem is avoided, sincethe edge of the neck during the sealing of the neck to the edge of thestem is immovably locked in position, while on the other hand, absoluteuniformity of wall thickness at the sealing-in points is always insuredby virtue of the positive-and limited elongation of the neck ofall bulbsworked consecutively at a number of positions.

The drawing herewith illustrates the rotatable holder head of asealing-in machine (see which is in gensaid Mitchell and atent1,453,594, is provided in operator at the loading position, the stemhaving been previously provided with a filament The bulb' is placed withits neckd downwards, over the filament supports c and the stem 5, thebulb e restin on and being rotated by the rotatable bulb holders ,Theneck 03 of the bulb,

is so short that in the first working position of the machine, the edgeof the neck preferably somewhat flared protrudes, as shown in Figure 1,only slightly beyond the flare g of the saidstem, and insufiiciently forthe sealing-in of the stem, the edge of the flare being substantially atthe edge of the bulb neck, as was customary in the short neck method ofsealing-in used for many years, but now superseded by the longneckmethod of seal- '71. carried by a pullin memli er,

ing-in disclosed in Figures 7 to 9 of U. S. patent to Kremenezky N 0.941,996, November 30, 1909. The edge of the neck of the bulb is grippedperipherally by a gripper, which may conveniently comprise ieldingfingers such as the vertically guided forked'frame 2' which is .holderheads are disposed. By means of the said guided frame 71 and the fingersh, the

bulb e is held in position, and its neck is subcaused to move into thenext or's'econd workjected to tension by the stationary cam m.

After part of the bulb neck has been adequately heated in the firstworking osition as depicted, in 'Fi re 1, by means 0 burner flames aprefera ly arranged to strike the bulb neck tangentially, the holderhead is .ing position. During its movement into this second workingposlton, a strong mechanical .pull is exerted upon the softened neckpor- Z of the slot Z in the cam m.

tion by the gripper through the fingers it, since the forked frame 71and the fingers mounted on it are compelled by the roller is to moveslightly downward by the curvature he consequence j of this action, asshown in Fig 2, is that the neck of the bulb issomewhat lengthened, sothat the lower ed 9 of the neck now projects somewhat fart er .beyondthe edge of flare g of the stem 1). While in this second workingposition, the bulb neck is subjected to additional heating bytangentially placed burner flames a, and also w ile moving out of thissecond working positon toward the thlrd positon the neck is furtherpositively lengthened by the further pull of the fingers has the rolleris of the forked frame i passes into the curvature Z of the slot Z. Thebulb neck after leaving the second workin posipose,in the workingposition depicted in igedge of the flare.

tion is lengthenedso much that in the ollowing or third working positonsufiicient length has been provided to permit the safe sealingm of thestem into the bulb. For this urure 3, with the neck d of the bulb being,as before, firmly gripped by the fingers h, the bulb neck in the usualway is subjected to the action of radially disposed sealing-in fires orflames a which seal the bulb neckto the The softened portion of the necklocated below the flare of the stem may incidentally for instance, ashere shown, beplaced firmly and snugly against the circumference of acone-shaped bushing o of the stem spindle 11. There is then formed achamber between the edge of the flare and the conical bushing, and inthe next working stage, asshown 1n Figure 4,*the surplus neck may be cutofi in the well known way by softening a narrow zone by. flames a, andalso .by a current of air supplied through a verticalbore p of the stemspindle a and directed outwardly by radial holes 9 provided immediatelybelow the sealing-in points, blowing out the softened glass of the neckdirectly below the sealing-in point until it is thin and is easilysevered by the flames. v

After having passed through the unloading positions for removal of thesealed lamp, and a position where the surplus portion of the neck isremoved from the stem spindle,

the forked frame 21 with fingers h is again raised by the curved slot Zof the cam into the position shown in .Fig. 1, and the head is,

ready to receive a new bulb and stem.

Instead of severing the surplus neck by.

blowing out the softened glass by an air current the zone on. the neckheated to a high temperature'can be severed in the well known ways as bya toolthrust into the softened material of the. neck immediately belowthe sealing zone, by tearing off the surplus, or merely by means ofpointed flames directed upon the neck.

The elongation of the bulb neck durin the first stage of the workingprocess, w en the bulb neck is down, can also be obtained by loading thepulling device with sufiicient weight, but in this case, it is necessaryto lock thepulling device after the desired elongation of the neck hasbeen obtained, in order that the sealing-in may be done in all caseswith the stationary.

The elongation of the bulb vneck roduc'ed rior to the sealing-in propercan,-i desired,

pull down device e producedby one singlemechanical pullon changin fromone workin position to the other. owever, when sea ing in large bulbs,the elongation 'of the bulb neck may also be effected in more than twoworking stages. The conical bushing 0 can be" made adjustablein heighton the stem spindle a; but, if desired, it 'may also be dispensed with,

if the surplus neck is cut off mechanically or b the aid of pointedflames.

hat I claim as new and desire to secure by Letters Patent of the UnitedStates is of the bulb immediately adjacent its edge,

ulling the ed e of the neck away from the reduced ulb to a pre eterminedextent to elongate the plastic neck and thereby draw its edgeconsiderably beyond the edge of the stem,-

holding the ed e of said neck immovable with reference to the ulb in theposition into which it has been drawn and heating to a highertemperature the hot elongated neck at a zone adjoining the edge'of thestem while the edge no 7 said neck immovable with reference to the.

edge of the bulb, heatin mined'distance to stretch the neck a bulb whichcomprisesholding the stem inside the' bulb neck with its edgesubstantially at the edge of the bulb neck, heating the bulb neck alonga zone immediately adjacent its edge, gripping the edge of the bulb neckand pulling it away from the bulb a predetermined distance to stretchthe hot plastic neck 'over the stem, holding the edge of said neckimmovable with reference to the bulb in ,the position into which it has.been drawn, further heating the hot elongated neck along a zoneadjoining the edge of the stem while the edge of said neck is 111 saidposition to seal the stem and the wall of'the bulb neck together, andremoving the sur lus neck by severing the bulb neck imme iately belowthe stem.

3. The method of sealing a stem into a bulb which comprises positioningthe stem in the bulb neck with its edgev substantially at the the bulbneck immediately adjacent its e geuntil it is plastic and stretching itto while plastic over. the stem by successive steps until the edge ofthe neck is considerably beyond the edge of the stem, holding the edgeof said neck immovable with referenceto t e bulb in the position drawnand then, while the elongated neck is still hot, and while the edge ofsaid neck is in said position heating a zone of the neck immediatelyadjacent the edge of the stem to seal .the walls of the elongated bulbneck'to the edge of the stem.

4. The method of sealing a stem into a bulb which consists inpositioning the stem in the bulb neck with itsedge substantially'at theedge of the bulb neck, heatin the bulb neck along a zone immediately aacent its edge to render it plastic, seizing the edge and u 1- inglongitudinally of the neck a pre eterover the stem and thin its walls,holding the edge of bulb in the position into which it has been drawnand then while said wallsare' still hot and while the edge of said neckis in said posi- P tion sealing the edge of the stem to thehot thinnedwalls of the neck.

5. In a device of the character described,

the combination of a bulb holder, a stem holder for holding a stemin-the neck of the bulb with its edge substantially a predeterminedextent p into which it has been atthe edge of the neck of the bulb forheating the neck of the bulb in said holder along a zone immediately adjacent its edge, a bulb neck gripper for gripping the edge of the bulbneck and movable with reference to the bulb holder to a predeterminedextent sufiicient only to stretch the neck of the bulb over the stem onsaid holder until said stem is well within but out of contact with thebulb neck and actuating means for moving said bulb neck gripper awayfrom the bulb holder to said predetermined extent only and then holdingerence to said holder while said burners seal the walls of theelongatedbulb neck to the edge of said stem. 7

- 6. In a device of the character described, the combination of a headmounted to travel through several positions in succession and comprisinga bulb holder, a stem holder, and a gripper for seizing the neck of abulb in said holder, said gripper being from said holder to carry theedge of the neck of said bulb well beyond the stem on said stem holder,burners mounted at some of said ositions to heat the neck of a bulb insaid holder, and actuating means responsive to movement of said headfrom one position to the next for moving said gripper relative to saidholder.

7. In a device of the character described, the combination with a bodilymovable head mounted to move into two positions in succession andcomprising a bulb holder, a stem holder in registry with said bulbholder and a bulb neck gripper mounted to' move out of its normalposition and away from said bulb holder into a remote position to pullthe edge of the neck of a bulb in said bulb holder beyond the edge of astem on said stem holder, of burners mounted at the first position toheat the neck of a bulb in said bulb holder adjacent the stem,sealing-in burners mounted at the second position to direct a flame atand below the edge of the stem, a stationa cam mounted adjacent the pathof said hea and connections between said cam and said gripper, said cambein shaped to move said gri per from its normal position to its remoteosition during travel'o said head from the first position to the secondand to hold it in in said bulb holder, burners movable away remoteposition during the sealing-in of the I stem. 7

In witness'whereof, I have hereunto set my hand this 18th day of March,1925.

HERMANN REMANE.

